It's recommended practice to set a limit on all mailboxes to protect your
server. The limit depends on the size of your organization, the type of work
that is being done, the email culture of your organization, hardware limits
of the mail server, anticipated growth during the write-off time of the
server etc...
It's not just a simple decision based on looking at what your "neighbors"
are doing. Asking "why" they are doing it that way will be more useful
though ;-)
